This invention relates to an apparatus for the flow-through treatment of textile material, nonwovens, or paper, with a gaseous or liquid treatment medium circulated in the entire apparatus. The apparatus comprises a permeable drum as a conveying element subjected to throughflow from the outside toward the inside, the drum being under a suction draft and having end plates at the end faces, and being covered on its periphery with a screen-type cover, sheet metal strips extending in the axial direction of the drum being arranged between the end plates of the drum, the extension in width of these sheet metal strips running substantially in the radial direction, and connecting elements which connect the sheet metal strips being provided in the peripheral direction between the sheet metal strips.
An apparatus of this type has been known from German Patent No. 1,946,376. The connecting elements consist of spacers associated with each sheet metal strip, these spacers being of a U shape and being welded to the sheet metal strips with their rear side. A more advantageous structure is disclosed in German Patent Application No. P 38 02 791.7 and corresponding U.S. Pat. No. 4,811,574. In this structure, these connecting elements are replaced by readily mountable spacers joined to the sheet metal strips by screws or rivets. Since these connecting elements taper radially outwardly into a web section, the maximum width of which is equal to the sheet metal thickness of the axially extending sheet metal strips, this sieve drum structure provides an optimum permeability of up to 90% for traversing fluid. The maximum permeability is attained where the strength of the sieve drum has reached its still permissible minimum. The strength is determined by the wall thickness of the axially extending sheet metal strips and, of course, also by the wall thickness of the connecting elements.